Confirmation of deafness in infancy. (1/154)

AIM: To assess delay in confirming hearing impairment in infants identified by universal neonatal screening and to investigate the causes. PATIENTS: Infants identified from 25 199 babies screened from January 1992 to December 1997. METHODS: A two stage transient evoked oto-acoustic emission test (TEOAE), with a threshold auditory brainstem response (ABR) recording undertaken on those who failed. The screen identified infants with a permanent congenital hearing impairment (PCHI) averaging 40 dBnHL or worse in the best ear. Those with less impairment were also ascertained. The positive predictive value (PPV) of the ABR test and measures of delay between identification and eventual diagnosis were analysed. RESULTS: A targeted PCHI was found in 1.18/1000 neonates. The PPV of the ABR for confirming a targeted PCHI was 100% when the ABR threshold was >/= 80 dBnHL. Nine of 11 infants with this threshold had severe or profound permanent deafness. The delay from ABR to audiological certainty was about 1 month-diagnosis was confirmed around 3 months. There was uncertainty when the ABR was 40-80 dBnHL. The PPV was 60% and 8% when the ABR thresholds were 70 dBnHL and 50 dBnHL, respectively. 85 of 111 infants with ABR thresholds in this range had a temporary conductive impairment. Their early diagnosis depended upon the type and degree of hearing impairment and diagnosis was delayed to about 8 months in these infants. CONCLUSIONS: Hearing impairments identified by universal screening are delayed in all but those with severe or profound bilateral PCHI. This delay can be reduced by applying in early infancy a battery of audiological tests and requires further exploration.  (+info)

Otolaryngological findings in congenital nasolacrimal duct obstruction and implications for prognosis. (2/154)

AIM: To investigate otolaryngological abnormalities associated with congenital nasolacrimal duct obstruction (CNLDO) and their effect on the prognosis. METHODS: 65 consecutive cases of CNLDO were followed up with routine otorhinolaryngological examination with tympanometry. RESULTS: Otitis media with effusion (OME) and uvula bifida were detected in 44.6% and 9.2% of the children, respectively. Medical treatment and probing were less effective in patients with OME (p<0. 05). CONCLUSIONS: OME and uvula bifida are significant anomalies associated with CNLDO and the former has a marked effect on the prognosis. This finding may help to determine the patients who will need further treatment after massage and probing.  (+info)

Tympanometry for diagnosis and treatment of otitis media in general practice. (3/154)

OBJECTIVE: The aim of this study was to evaluate the role of tympanometry for diagnosis, treatment and follow-up of otitis media in general practice. METHODS: The results from otoscopy performed by 40 physicians in general practice in Vejle County, Denmark were combined with the clinical condition and this was recorded as the preliminary decision about diagnosis, treatment and follow-up. Subsequently, tympanometry was performed in 3176 children aged between 1 month and 16 years; a total of 6352 tympanometries. With this added knowledge, a final decision about diagnosis, treatment and follow-up was recorded. The practitioners were trained in performing tympanometry including the interpretation of the results. Simultaneously, they were involved in the establishment of guidelines for diagnosis, treatment and follow-up of otitis media in general practice. The main outcome measures were changes between preliminary and final decisions about diagnoses, treatments and follow-up regimens. RESULTS: Tympanometry was performed successfully in 87.7% of the children, and in 26.4% changes in diagnoses were found. However, tympanometry did not influence the distributions of the main outcome measures in the sample as a whole. Uncomplicated cases were checked in general practice and referrals to specialists were not increased. CONCLUSION: Tympanometry can be performed successfully in general practice after appropriate instruction. In 26.4% of children, the diagnoses were changed, which may result in more appropriate treatment and follow-up. Tympanometry is a clinically relevant supplement to the examination of a child in general practice.  (+info)

Behaviour and developmental effects of otitis media with effusion into the teens. (4/154)

OBJECTIVE: To examine whether behavioural or cognitive sequelae of otitis media with effusion (OME) continue into late childhood and the early teens (11-18 years). SETTING: Data from a large multipurpose birth cohort study: the Dunedin multidisciplinary health and development study. PARTICIPANTS: Around 1000 children from the study. The main independent variable of interest was otological status of the child up to age 9. MAIN OUTCOME MEASURES: Parent and teacher rated behaviour problems, including antisocial, neurotic, hyperactive, and inattentive behaviours, and tests of academic achievement including intelligence quotient (IQ), reading, and spelling were available in a high proportion of the cohort at ages 11 to 18 years. RESULTS: After adjustments for covariates such as socioeconomic status, hyperactive and inattentive behaviour problems were evident as late as 15 years, and lower IQ associated with OME remained significant to 13 years. The largest effects were observed for deficits in reading ability between 11 and 18 years. CONCLUSIONS: No previous study considering behaviour problems as an outcome has followed children long enough to determine whether some of the early sequelae of OME are still present in the early to late teens. Some developmental sequelae of OME, particularly deficits in reading ability, can persist into late childhood and the early teens.  (+info)

Does early detection of otitis media with effusion prevent delayed language development? (5/154)

OBJECTIVE: To consider whether earlier detection of otitis media with effusion (OME) in asymptomatic children in the first 4 years of life prevents delayed language development. METHODS: MEDLINE and other databases were searched and relevant references from articles reviewed. Critical appraisal and consensus development were in accordance with the methods of the Canadian Task Force on Preventive Health Care. RESULTS: No randomised controlled trials assessing the overall screening for OME and early intervention to prevent delay in acquiring language were identified, although one trial evaluated treatment in a screened population and found no benefit. The "analytic pathway" approach was therefore used, where evidence is evaluated for individual steps in a screening process. The evidence supporting the use of tools for early detection such as tympanometry, microtympanometry, acoustic reflectometry, and pneumatic otoscopy in the first 4 years of life is unclear. Some treatments (mucolytics, antibiotics, steroids) resulted in the short term resolution of effusions as measured by tympanometry. Ventilation tubes resolved effusions and improved hearing. Ventilation tubes in children with hearing loss associated with OME benefited children in the short term, but after 18 months there was no difference in comparison with those assigned to watchful waiting. Most prospective cohort studies that evaluated the association between OME and language development lacked adequate measurement of exposure or outcome, or suffered from attrition bias. Findings with regard to the association were inconsistent. CONCLUSIONS: There is insufficient evidence to support attempts at early detection of OME in the first 4 years of life in the asymptomatic child to prevent delayed language development.  (+info)

Auditory system: Peripheral nonlinearity and central additivity, as revealed in the human stapedius-muscle reflex. (6/154)

Human stapedius-muscle contractions in response to 3-kHz, 20-msec tone bursts were determined indirectly by measuring the associated acoustic-impedance changes at the tympanic membrane with an acoustic bridge. The measurement was possible because the bridge practically eliminates the effect of the ear-canal air volume interposed between the tympanic membrane and the tip of the measuring tube. By using burst pairs, temporal additivity of the muscle responses was demonstrated both when the stimulus bursts were presented contralaterally to the measured impedance changes and when the first burst was presented ipsilaterally. The summation time constant was on the order of 200 msec, much longer than the twitch time constant of the muscle fibers. Therefore, the summation had to take place in a nucleus preceding the stapedius muscle. The magnitude of the muscle response obeyed a compressive function paralleling the loudness function up to sound pressure levels of at least 120 dB.  (+info)

Practical screening priorities for hearing impairment among children in developing countries. (7/154)

Routine screening for hearing impairment in childhood is now widespread in industrial countries, although there is considerable controversy over the most efficient techniques and procedures. In most developing countries, however, routine screening programmes for hearing impairment do not currently exist. The problems involved in implementing screening programmes in developing and industrial countries are very different, and in selecting screening procedures for a particular population the following factors have to be taken into consideration: the environmental test conditions; the availability of resources for equipment and the training of testers; the local attitudes towards disability; the level of hearing impairment that may cause handicaps; and the major types of pathology causing hearing impairment. We suggest that in developing countries children should be screened at school entry using a simple field audiometer and that the external ear be inspected for the presence of a discharge. There is an urgent need to develop reliable and simple screening procedures for infants and young children; where possible, all children should be screened for severe or significant hearing impairment before the age of 2 years. No screening should, however, be implemented until appropriate follow-up services are available.  (+info)

Impedance analysis of the organ of corti with magnetically actuated probes. (8/154)

An innovative method is presented to measure the mechanical driving point impedance of biological structures up to at least 40 kHz. The technique employs an atomic force cantilever with a ferromagnetic coating and an external magnetic field to apply a calibrated force to the cantilever. Measurement of the resulting cantilever velocity using a laser Doppler vibrometer yields the impedance. A key feature of the method is that it permits measurements for biological tissue in physiological solutions. The method was applied to measure the point impedance of the organ of Corti in situ, to elucidate the biophysical basis of cochlear amplification. The basilar membrane was mechanically clamped at its tympanic surface and the measurements conducted at different radial positions on the reticular lamina. The tectorial membrane was removed. The impedance was described by a generalized Voigt-Kelvin viscoelastic model, in which the stiffness was real-valued and independent of frequency, but the viscosity was complex-valued with positive real part, which was dependent on frequency and negative imaginary part, which was independent of frequency. There was no evidence for an inertial component. The magnitude of the impedance was greatest at the tunnel of Corti, and decreased monotonically in each of the radial directions. In the absence of inertia, the mechanical load on the outer hair cells causes their electromotile displacement responses to be reduced by only 10-fold over the entire range of auditory frequencies.  (+info)

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